1 files changed, 73 insertions, 0 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index c5257316f4b9..6b186750e9be 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -108,6 +108,79 @@ static inline void *get_wq_data(struct work_struct *work)
 	return (void *) (work->management & WORK_STRUCT_WQ_DATA_MASK);
 }
 
+static int __run_work(struct cpu_workqueue_struct *cwq, struct work_struct *work)
+{
+	int ret = 0;
+	unsigned long flags;
+
+	spin_lock_irqsave(&cwq->lock, flags);
+	/*
+	 * We need to re-validate the work info after we've gotten
+	 * the cpu_workqueue lock. We can run the work now iff:
+	 *
+	 *  - the wq_data still matches the cpu_workqueue_struct
+	 *  - AND the work is still marked pending
+	 *  - AND the work is still on a list (which will be this
+	 *    workqueue_struct list)
+	 *
+	 * All these conditions are important, because we
+	 * need to protect against the work being run right
+	 * now on another CPU (all but the last one might be
+	 * true if it's currently running and has not been
+	 * released yet, for example).
+	 */
+	if (get_wq_data(work) == cwq
+	    && work_pending(work)
+	    && !list_empty(&work->entry)) {
+		work_func_t f = work->func;
+		list_del_init(&work->entry);
+		spin_unlock_irqrestore(&cwq->lock, flags);
+
+		if (!test_bit(WORK_STRUCT_NOAUTOREL, &work->management))
+			work_release(work);
+		f(work);
+
+		spin_lock_irqsave(&cwq->lock, flags);
+		cwq->remove_sequence++;
+		wake_up(&cwq->work_done);
+		ret = 1;
+	}
+	spin_unlock_irqrestore(&cwq->lock, flags);
+	return ret;
+}
+
+/**
+ * run_scheduled_work - run scheduled work synchronously
+ * @work: work to run
+ *
+ * This checks if the work was pending, and runs it
+ * synchronously if so. It returns a boolean to indicate
+ * whether it had any scheduled work to run or not.
+ *
+ * NOTE! This _only_ works for normal work_structs. You
+ * CANNOT use this for delayed work, because the wq data
+ * for delayed work will not point properly to the per-
+ * CPU workqueue struct, but will change!
+ */
+int fastcall run_scheduled_work(struct work_struct *work)
+{
+	for (;;) {
+		struct cpu_workqueue_struct *cwq;
+
+		if (!work_pending(work))
+			return 0;
+		if (list_empty(&work->entry))
+			return 0;
+		/* NOTE! This depends intimately on __queue_work! */
+		cwq = get_wq_data(work);
+		if (!cwq)
+			return 0;
+		if (__run_work(cwq, work))
+			return 1;
+	}
+}
+EXPORT_SYMBOL(run_scheduled_work);
+
 /* Preempt must be disabled. */
 static void __queue_work(struct cpu_workqueue_struct *cwq,
 			 struct work_struct *work)